Electric fuse device



June 17, 1941- s. R. SMITH, JR

ELECTRIC FUSE DEVICE Filed Jan. 1l, 1939 fla. I

27 0 INSULATION Inventorsdney F2. Smabhgr.,

by 7V C.

- I-iis Attorney;

Patented June 17, 1941 ELECTRIC FUSE DEVICE Sidney n. smith, Jr., Pittsfield, Mass., assignor to General Electric Company, a corporation of New York Application January 11, 1939, Serial No. 250,3-73

9 Claims.

The present invention relates to electric fuses, and more particularly to so-called secondary fuses which are suitable for such purposes as protection of transformers from.- secondary 1 vconductors connected therewith, while giving readily observable indication of fuse operation.

A further object of the invention is the provision of an improved form of fuse support, which is employable for suspension mounting of cartridge fuses on electric line conductors and like supporting means, and which is constructed so4 as to afford eective weather protection for fuses accommodated therein.

Other objects and the details of that which I consider to be novel and my invention wiil become apparent fromthe following description and the claims appended thereto, taken in conjunction with the accompanying drawing in which Fig. 1 shows, in longitudinal section, a fuse device embodying the present invention, with the fuse cartridge in connected position;

Fig. 2 shows the device of Fig. 1 with the cartridge in dropped-out position following fuse operation, and Fig. 3 illustrates diagrammatically an exemplary installation of the fuse device of Fig. 1.

Although the device of the present invention is suitable for mounting in various ways, depending upon the particular location at which fused protection is desired, the device is illustrated for purposes of example as installed in conjunction with a strain insulator of a form common in the art. This insulator, designated I0, serves mechanically to join, in a well-known manner, two line conductors I I and I2 with the conductor I2 attached to the insulator so as to leave an end thereof free for connection purposes as indicated in Fig. 3.

The fuse support of the present invention includes a hollow tubular insulator I3 constructed of glass or other suitable material which is transparent and has the required mechanical strength and electric insulation characteristics. Preferably this insulator is provided with spacedapart circumferentially extending ridges I4 or other suitable means for prevention of electric creepage across the insulator. Securely ailixed to the insulator and closing the upper end of the longitudinal bore therein, is a metallic terminal piece I5 which is provided, externally, with a split connector stud I8, contact clip I1, and clamping nut IB for attachmentto a line conductor Ii or like support for the insulator. Terminal piece I5 is provided internally of the insulator with a tubular socket formed by a plurality ,of resilient contact fingers I9 which are narod/'at their extremities, as indicated at 20, so as to facilitate insertion of the end of a cartridge fuse into the socket. A second metallic terminal piece 2l is anixed to the lower end of insulator I3. This latter terminal piece may be constructed of two parts, as illustrated, or may be a single piece similar to upper terminal I5. Terminal piece 2| is provided with a plurality of resilient contact fingers 22 projecting into the lower end of the bore in insulator I3 in a manner to form a tubular socket for engagement with the lower end of a fuse cartridge in the insulator bore. 'Ihe inner free ends of fingers 22 are flared, as indicated at 23, so as to facilitate removal of a fuse cartridge fromv the insulator in a manner to be described. Terminal piece 2l is provided externally with a socket 24 and clamping screw 25 for connection of a lead or conductor, such as the free end of conductor I2, thereto.

I have provided a special form of indicating fuse cartridge which is particularly suitable for use with the fuse support hereinbefore described. 'Ihe fuse holder of this cartridge comprises an insulating tube 26 with terminal caps 21 and 28 screw-threaded on the upper and lower ends respectively of the tube. The cartridge is insertable into the bore of insulator I3 through the tubular socket formed by contact ngers 22, and terminal cap 28 is provided with a ringshaped handle 30 for aid in manipulation of the cartridge into and out of the insulator. When in operative position, shown in Fig. 1, the upper terminal cap 2'I of the cartridge is frictionally engaged by contact fingers I9 and the lower terminal cap 28 is frictionally engaged by contact fingers 22.

Within the fuse holder is a common form of fuse link including a fuse wire 3l and a strain wire 32. One end of this fuse link is anchored to lower terminal cap 28 in any suitable manner, as by soldering, as indicated at 33. 'I'he other end of the fuse link has a terminal shank 34 which is longitudinally movable, in the man- Y support.

ner of a plunger, through an opening 35 in the end of terminal cap 21, and an opening 36 in a. washer 31 secured on the upper end of tube 26 by means of cap 21. Insurrounding relation to shank or plunger 34 is a coiled compression spring 38 which is secured at its inner end between cap 21 and washer 31. The outer end of the spring is secured tothe button head cap 39 of the fuse link by means of a spun-over cap 40. Normally the spring tends to impel plunger 34 from the upper end of the fuse cartridge but is restrained by the intact strain wire 32 of the fuse link. When the cartridge is in its operative position, shown in Fig. 1, the end of plunger 34 and the spring 38 are accommodated in a recess 4I -in upper terminal piece I5, and cap 40 bears against the abutment formed by the base of the recess. l f

- Upon rupture of fuse wire 3| and strain wire 32 due to excess current, the spring driven plunger 34-38 functions with sufficient force to eject the fuse cartridge from the upper terminal socket formed by contact fingers I9, and also draws out the arc in the fuse tube. At the same time, terminal cap 28V is forced out of the socket formed by fingers 22. This permits the cartridge to drop since tube 26 is of less diameter than cap 28 and therefore is not frictionally restrained by fingers 22. Finally, when the Acartridge reaches the position illustrated in Fig. 2, it is held by engagement of the flared portions 23 of fingers 22 with terminal cap 21. Under these conditions the fuse holder of the cartridgeis electrically isolated from upper terminal piece I5 and the conductor connected therewith, while the lower end of the cartridge depends below the bottom of insulator `I3 to give readily observable indication of fuse operation.

By pulling down on ring 30 with suiiicient force,

terminal cap 21 may be caused to slide by the ared portions 23 of ngers 22 so that the blown cartridge may be withdrawn from the insulating support, thereby providingl for installation of al new'cartridge in the support. If desired, conmay be readilydetected due to the transparency of the walls of insulator I3.

Common forms of non-ejecting indicating fuse tions, such as at the ends of rural, lines, where it is desired to have reliability of fuse protection with minimum expense.

- What I claim as new and desire to secure by Letters Patent of the United States is:

1. A line suspension fuse device comprising in combination a hollow insulator having a fuse cartridge receiving bore open at one end for insertion of a fuse cartridge thereinto, spaced terminal elements carried by said insulator, one oi said terminal elements having a clamping part adapted to be attached to an electric line conductor for supporting the fuse device directly on said conductor, a unitary fuse cartridge removably disposed in saidbore and including a fusible element, means releasably retaining said cartridge in said bore with said fusible elementelectrically connected between said terminal elements, and means, forming an integral part of said cartridge, operative in response to operation of said fusible element to effect ejection of the cartridge at least partially from said open end of said bore.

2. A line suspension fuse device comprising in combination, a hollow insulator having a fuse cartridge receiving bore open at one end for insertion of a fuse 'cartridge thereinto, spaced terminal elements affixed to said insulator, one of said terminal elements having a clamping part adapted to be attached to an electric line conductor for supporting the fuse device directly on said conductor, a fuse cartridge having a fusible element therein, means releasably retaining said cartridge in said bore with said fusible element electrically connected between said terminal elements, means operative upon operation of said fusible element to impel said cartridge in the cartridges, such as of the black powder type, also may be employed with the improved fuse support of my present invention. In such case, indication Aof the blowing of the fuse is readily observable through the transparent walls of insulator-I3 Moreover, through the employment of suitable adapters, it is possible to use different sizes and ratings of fuse cartridges in the fuse Thus the fuse support has the important advantage that it may be used for suspension mounting of standard forms of fuse cartridges as well as 'for mounting of the special indicating form of fuse cartridge herelnbefore described.

From the foregoing it will be seen that, due to the simplicity and low cost of the fuse support and its weatherproof construction, together with the ease of mounting the support on a line conis extremely well suited for secondary installadirection of said open vend of said bore,A and means to stop the cartridge in a partially ejected position wherein the cartridge is electrically isolated from at least one of said terminal elements and wherein a part of thecartridge projects from said open end of the bore.

3. A fuse device comprising in combination a hollow insulator defining a'bore open at one end for insertion of a fuse cartridge thereinto, terminal elements aixed to said insulator respectively adjacent opposite ends of said bore, a

unitary fuse cartridge removably disposed in said bore and including a fuse link and a plungerlike member normally occupying a retracted position, said member being arranged to lbear -tively adjacent opposite ends of said bore, a

unitary fuse cartridge removably disposed in 'said bore and including a fuse link and a plunger-like member normally occupying a retracted position, said member being arranged to bear against an abutment adjacent the end ofamener.

tion of said fuse link to impel said cartridge in the direction of said open end of said bore, and means to stop the cartridge in a partially ejected position electrically isolated from one of said terminal elements and with a part of the cartridge projecting from said open end of the bore.

5. A fuse device comprising in combination a 4hollow insulator defining a bore open at one end bei' being arranged to bear against an abutment adjacent the end of said bore opposite to said open end and being operative upon rupture of said fuse link to eject said cartridge at least partially from said open end of the bore.

6. A fuse device adapted for mounting on an electric line conductor or the like and comprising a hollow insulator dening a bore open at one end for insertion of a fuse cartridge thereinto, a pair of terminal elements aixed to said insulator respectively adjacent opposite ends of lsaid bore, one of said terminal elements having means for clamping attachment to a supporting conductor and the other of the terminal elements having means for connection of a second conductor thereto,V a unitary fuse cartridge removably disposed in said bore and having a fuse link therein, means releasably retaining said cartridge in said bore with said fuse link electrically connected between said terminal elements, and means operative upon rupture of said fuse link to eilect ejection of said cartridge at least partially from said open end of said bore.

7; A fuse device adapted for mounting on an electric line conductor or the like and comprising a hollow insulator `defining a bore open at one end for insertion of a fuse cartridge thereinto, a pair of terminal elements axed to said insulator respectively adjacent opposite ends of said bore, one of said terminal elements having means for clamping attachment to a conductor for supporting the fuse device and the other terminal element having means for connection of a second conductor or electric lead thereto, a unitary fuse cartridge removably disposed in said bore and having a spring driven member arranged to bear againstV a part xed relative to said insulator, means including a fuse link in said cartridge normally restraining said member in a retracted position, contact means conductively associated respectively with said Vterminal elements and rictionally engaging said cartridge to retain the latter in said bore, and means cooperative With said spring driven member upon rupture of said fuse link toveiect ejection of said cartridge at least of said bore.

8. A fuse device adapted for mounting on an electric line conductor or the like and comprising a hollow insulator defining a fuse cartridge receiving bore open atlone end for insertion of a fuse cartridge thereinto, a unitary fuse cartridge removably disposed in said bore, a pair of terminal elements affixed to said insulator respectively adjacent the opposite ends of said bore, and contact means conductively associated respectively with said terminal elements and respectively engaging spaced terminals of said cartridge to retain the cartridge in said bore, one

of said terminal elements having means for detachable connection to a conductor for supporting the fuse device and the other of the terminal elements having means for connection of a second conductor or electric lead thereto.

9. A fuse support adapted for mounting on an electric line conductor or the like and comprising a hollow insulator having transparent Walls delining a fuse cartridge receiving bore open at one end for insertion of a. fuse cartridge thereinto, a pair of terminal elements aiixed to said insulator respectively adjacent opposite ends of said bore, one of said terminal elements having means :for attachment to a conductor for supporting said insulator and the other of the term'inal elements having means for connection of a second conductor thereto, and contact means conductively associated respectively withsaid terminal elements and ,engageable respectively with spaced terminals of a fuse cartridge in said bore.

SIDNEY R. SMITH, Ja.

partially from the open end 

